Operations Blog: Deep Dive into SNOWsat Grooming Technology

This is the view from the operator’s seat of one of our winch cats (a powerful snowcat that uses a steel cable and a boom). In this photo, you can see that the monitor has a split-screen view.

On the left side of the screen, operators can see snow depth; on the right, operators can view a terrain map. Each view is a useful tool that can be used either separately or simultaneously. The split view is most helpful when you need to see how the snow depth corresponds with the underlying terrain.

During the height of winter, when the snow depth readings are all fairly significant and you can expect most things to be buried, it is more helpful to look at just the terrain view. In the springtime, as things start to melt out, it is helpful to see both or just the snow depth view.

Take a look at this view of the terrain at the top of Siberia ridge:

• The 224″ at the top left of the screen is the snow depth in this spot. Yes, that’s 224 inches!
• The green strip shown here is where the summer road was mapped. It is always helpful to see where the edges of roads are; road maintenance is the most important piece of keeping a ski resort operational.
• This view is NOT showing snow depth, but the terrain. In the tiny square on the top left, THAT view is snow depth.

See those bright patches of blue, green, and purple? Those are spots where the snowpack is melted out, and our operators need to repair them.

In the springtime, during an average year (400 inches or so of snowfall), it is normal to see mostly blue coverage on the screen. Our operators would typically be scraping snow from these blue patches and adding it to purple or red patches in the hopes of turning them green. This year, because we received such a significant amount of snowfall (more than 720 inches), you can see that most of this run is dark yellow, which means the snow depth is above 60 inches.

Another neat feature on SNOWsat is something our operators refer to as a “pass counter.” Essentially, it is a function that records travel frequency. It colors where your machine has been and then the colors change if you go over that area again and again. It tracks both efficiency and location.

As you can imagine, these tools are especially useful in whiteout, low-visibility conditions to see if you’re where you’re supposed to be. On days when you can barely see in front of you, SNOWsat is crucial for proper navigation and execution.

With the old system our snowcats used, location data only would sync up with the server every time you drove by an area with WiFi. Now, our snowcats each individually have 4G LTE, so the location data you see on the screen is real-time. Not only can our operators see where the other machines are, but they can also see where winch cat cables are and their current location. The white line across the screen in this photo shows where a winch cable is located.

Here is a split-screen view of Times Square Face. If you look at the Snow Depth view on the left-hand side, you can see where one of the roads curves through the top of the run. As the snow melts, this road is obstructing the run: See those patches of lighter yellow in the Snow Depth view? These are areas that don’t have quite as much snow on them that are in need of replenishment.

After analyzing the conditions and making a plan for how to fill in the area, the operator begins by adding snow to the area where the underlying road is. Look closely: You will see snow stacked up at the top of the run.

Once the right amount of snow has been moved into that area, a travel route for work is established. This means that the snowcat operator drives the machine over the pile of added snow.

Next, once the snowcat has driven over the new snow, the area is graded out into an even surface and blended into the run.

Finally, the operator will make a series of passes over the run with the machine’s tiller down. The tiller is the attachment on the back of a snowcat that creates that “corduroy” texture you see first thing in the morning.

LiDAR stands for Light Detection and Ranging, and it is a remote sensing method that uses light in the form of a pulsed laser to measure variable distances to the earth. In PistenBully snowcats, LiDAR is used to create a 3D map of the terrain and snow depth. In the summer months at Palisades Tahoe, we have mapped our mountains so that in the wintertime, the LiDAR technology compares that summer map to the existing snowfall on the mountain.

Right now, we only have a few snowcats with the new LiDAR system, but this is a feature that we will continue to invest in as our PistenBully fleet expands. The LiDAR system can take up to 200,000 measurements per second, which provides us with incredibly accurate data on the snow depth, bumps, and other features on our ski runs. Additionally, the LiDAR system in our snowcats is equipped with GPS and other sensors, which allow us to track the location and movements of our snowcats as well.

Doze Lanes

One way we move huge amounts of snow around is by using what is known as a doze lane. Operators dig a wide, deep lane and push snow from higher up. The snow slides through the doze lane, sort of like a snowball effect, building as it cascades down the mountain.

This requires some expert maneuvering; it is a bit easier to manage a doze lane when you are in a winch cat, which means the snowcat is hooked up to a tower via cable. If you stop the machine in the wrong spot while working a doze lane, it is very easy to get stuck.

Cross Pushing

Another method of moving snow is what is known as “cross pushing.” It is where snow is moved across an area and then taken somewhere else. This is a more lengthy farming method to harvest deeper pockets of snow or to dig out infrastructure. In this video, you will see one snowcat operator pushing snow across and the other moving it to a different area.